DIN 1587 is the governing dimensional standard for sealing cap nuts. This page sets out the scope of the standard, reproduces the full size table it specifies, and lists the DIN/ISO/ASME cross-references commonly cited in datasheets and drawings.
DIN 1587 — Scope
DIN 1587 specifies the dimensions and tolerances of sealing cap nuts. Material, property class, surface finish and packaging are governed by separate documents in the same standards family (for example ISO 898-1 for the mechanical property classes of bolts and screws).
Tolerance & Product Grades
DIN 1587, alongside the related DIN 1587 entries on this site, specifies product grades (typically A or B for fine work and C for general engineering) and tolerance classes for the controlling dimensions. Choose the grade against the precision your application requires.
Dimensions Specified by DIN 1587
| Thread size | Pitch (mm) | Across flats s (mm) | Across corners e (mm) | Total height m (mm) | Dome diameter (mm) | O-ring seat | Reference standard |
|---|---|---|---|---|---|---|---|
| M5 | 0.8 | 8 | 8.79 | 10 | 8 | 4.5 x 1.5 NBR | DIN 1587 + O-ring |
| M6 | 1.0 | 10 | 11.05 | 12 | 10 | 5.5 x 1.5 NBR | DIN 1587 + O-ring |
| M8 | 1.25 | 13 | 14.38 | 15 | 13 | 7.5 x 2.0 NBR | DIN 1587 + O-ring |
| M10 | 1.5 | 17 | 18.90 | 18 | 17 | 9.5 x 2.0 NBR | DIN 1587 + O-ring |
| M12 | 1.75 | 19 | 21.10 | 22 | 19 | 11.5 x 2.0 NBR | DIN 1587 + O-ring |
| M16 | 2.0 | 24 | 26.75 | 28 | 24 | 15.5 x 2.5 NBR | DIN 1587 + O-ring |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Sealing Cap Nuts page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 1587
DIN 1587 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.
